Chain of power devices

ABSTRACT

Various implementations described herein are directed to methods for connecting power devices prior to deployment in a photovoltaic installation, for cost savings and easy deployment. Some embodiments disclosed herein include manufacturing a chain of power devices already coupled by conductors, and providing a mechanical assembly for convenient storage and deployment.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/478,526, filed Apr. 4, 2017, which claims benefit of U.S. ProvisionalPatent Application No. 62/318,303, filed Apr. 5, 2016, U.S. ProvisionalPatent Application No. 62/341,147, filed May 25, 2016, and U.S.Provisional Patent Application No. 62/395,461, filed Sep. 16, 2016, thecontents of which are incorporated herein by reference in theirentireties for all purposes.

BACKGROUND

Power devices may be electrically coupled to photovoltaic (PV)generators and configured the set the operating point of the generatorsto generate maximum power. They may also be coupled to power productionand/or storage units such as batteries, wind or hydroelectric turbinesand the like.

Power devices are often manufactured, packaged and sold as single units,leading to deployment which requires that each device be individuallycoupled to its power unit and the devices themselves coupled byconnecting electric cables between them.

Accordingly, there is a need for power device systems in which costs,time and complexity in deploying the power devices are reduced.

SUMMARY

The following summary is a short summary of some of the inventiveconcepts for illustrative purposes only, and is not intended to limit orconstrain the inventions and examples in the detailed description. Oneskilled in the art will recognize other novel combinations and featuresfrom the detailed description.

Embodiments herein may employ a string of photovoltaic power devices(e.g. DC/DC converters, DC/AC inverters, measuring and monitoringdevices) which may be deployed in photovoltaic installations. In someembodiments discussed herein, conductors may be used to couple powerdevices to one another during manufacturing to form a chain of powerdevices, with the chain packaged and sold as a single unit. The chainmay be deployed by coupling the power devices in the chain tophotovoltaic (PV) generators (e.g. one or more photovoltaic cells,substrings, PV panels, strings of PV panels and/or PV shingles). Thecoupling of power devices at the time of manufacturing may reduce costsand enable compact storage of the devices, and the easy deployment mayreduce installation time. Connecting power devices at the time ofmanufacturing may include directly connecting conductors (e.g. bysoldering or screwing the conductors into place within a power deviceenclosure) between adjacent power devices. Furthermore, preconnectingpower device may reduce the number of connectors (e.g. MC4™ connectors)featured in each power device from four (two connectors for connectingto a PV generator at the power device input and two connectors forconnecting between power devices at the power device output). Asconnectors may be costly components, substantial savings may berealized. Additionally, preconnecting power devices during manufacturingmay increase system safety. For example, if improperly connected,connection points between power devices may be susceptible tooverheating, arcing and/or other unsafe event which may result in fire.Preconnecting power devices during manufacturing without use ofconnectors may increase system safety by reducing the number ofconnection points from four per power device to two per power device.

Certain embodiments of illustrative power-circuit chains may be woundaround a storage spool similar to spools used for storing electricalcables, and deployed in photovoltaic installations by unrolling thespool and coupling the power devices to photovoltaic generators thepower devices unwound from the spool.

In some embodiments of illustrative power-circuit chains, a distancebetween adjacent power devices may correspond to an estimated distancebetween photovoltaic generator junction boxes in a photovoltaicinstallation, to enable adjacent power devices to be coupled to adjacentphotovoltaic generators. In some embodiments, more than one photovoltaicgenerator may be coupled to each power device. For example, in somesolar installations, two PV generators may be coupled in series and thetwo generators may then be coupled to one power device, in which casethe length between adjacent power devices may be about double thedistance between adjacent generators.

The photovoltaic power devices may include, but are not limited to,DC/DC converters, DC/AC inverters, devices configured to measure andmonitor photovoltaic parameters, communication devices, safety devices(e.g., fuses, circuit breakers and Residual Current Detectors) and/orMaximum Power Point Tracking (MPPT) devices. The power generation unitsmay include, but are not limited to, photovoltaic modules (e.g.photovoltaic cells, photovoltaic generators), batteries, wind turbines,hydroelectric turbines and fuel cells.

As noted above, this Summary is merely a summary of some of the featuresdescribed herein and is provided to introduce a selection of concepts ina simplified form that are further described below in the DetailedDescription. The Summary is not exhaustive, is not intended to identifykey features or essential features of the claimed subject matter and isnot to be a limitation on the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood with regard to the followingdescription, claims, and drawings. The present disclosure is illustratedby way of example, and not limited by, the accompanying figures. A morecomplete understanding of the present disclosure and the advantagesthereof may be acquired by referring to the following description inconsideration of the accompanying drawings, in which like referencenumbers indicate like features, and wherein:

FIGS. 1A-1E are part schematic, part block diagrams of illustrativephotovoltaic systems according to certain embodiments.

FIGS. 2A-2C depict photovoltaic power devices according to certainembodiments.

FIG. 3 is part schematic, part block diagram depicting a photovoltaicpower device according to certain embodiments.

FIGS. 4A-4C depict illustrative embodiments of strings of photovoltaicpower devices coupled by conductors.

FIGS. 5A-5C depict illustrative embodiments of portions of photovoltaicstrings, with a plurality of photovoltaic power devices coupled to eachother by conductors and coupled to photovoltaic generators.

FIG. 6 depicts an illustrative embodiment of a string of photovoltaicpower devices coupled by conductors, stored on a storage device.

DETAILED DESCRIPTION

In the following description of various illustrative embodiments,reference is made to the accompanying drawings, which form a parthereof, and in which is shown, by way of illustration, variousembodiments in which aspects of the disclosure may be practiced. It isto be understood that other embodiments may be utilized and structuraland functional modifications may be made, without departing from thescope of the present disclosure.

Since power devices may often be used in bulk (e.g., one power deviceper photovoltaic generator may be used in a solar installation includingmultiple photovoltaic strings, each string including ten, twenty or morephotovoltaic generators), costs may be reduced and deployment may beeasier by packaging power devices in a form which enables multipledevices to be strung out and deployed at one time, along a photovoltaicstring. Furthermore, use of a storage device such as a spool to windmultiple cable-connected devices around can make storage and deploymenteasier and cheaper.

Referring to FIG. 1A, illustrative photovoltaic installation 100 a mayinclude a plurality of photovoltaic (PV) modules 101 a-y. Photovoltaicgenerators may also be referred to as “photovoltaic modules”. Each PVgenerator 101 a-y may be coupled to a photovoltaic power device 102 a-y.

In some embodiments, one or more PV power device 102 a-y may comprise apower conversion circuit such as a direct current—direct current (DC/DC)converter such as a buck, boost, buck-boost, flyback and/or forwardconverter. In some embodiments, one or more PV power device 102 a-y maycomprise a direct current—alternating current (DC/AC) converter, alsoknown as an inverter or a microinverter. In some embodiments, one ormore PV power device 102 a-y may include a Maximum Power Point Tracking(MPPT) and/or Impedance Matching circuit with a controller, configuredto extract regulated (e.g. increased) power from the PV generator thepower device is coupled to. One or more PV power device 102 a-y mayfurther comprise a control device such as a microprocessor, DigitalSignal Processor (DSP) and/or a field-programmable gate array (FPGA). Insome embodiments, one or more PV power device 102 a-y may comprisecircuitry and/or sensors configured to measure parameters on or near thephotovoltaic generator, such as the voltage and/or current output by thegenerator, the power output by the generator, the irradiance received bythe generator and/or the temperature on or near the generator.

In the illustrative embodiment depicted in FIG. 1A, a plurality of PVpower devices 102 a-m are coupled in series, to form a firstphotovoltaic string 316 a. One terminal of the resultant photovoltaicstring 316 a may be coupled to a power bus, and the other terminal ofthe photovoltaic string 316 a may be coupled to a ground bus. In someembodiments, the power and ground buses may be input to system powerdevice 110. System power device 110 may comprise a DC/AC converter, andthe DC/AC converter may output AC power to the grid, home or otherdestinations. In some embodiments, the photovoltaic power devices maycomprise microinverters, and an additional inverter (e.g. part of systempower device 110) may not be included. In some embodiments, the powerdevices may output a time-varying DC signal which emulates a rectifiedsine wave, in which case system power device 110 may comprise afull-bridge circuit configured to convert the rectified sine wave to astandard, alternating sine wave. In some embodiments, system powerdevice 110 may include a combiner box for combining power from aplurality of photovoltaic strings (e.g. 316 a-316 n). In someembodiments, system power device 110 may comprise sensors/sensorinterfaces for measuring or receiving measurements of one or moreparameters (e.g. current, voltage, power, temperature etc.) associatedwith PV strings 316 a-316 n. In some embodiments, system power device110 may include one or more safety switches for disconnecting and/orshort-circuiting PV strings 316 a-316 n in case of a potentially unsafecondition or in response to a manual trigger (e.g. activating arapid-shutdown switch or button).

Since PV power devices of known systems may be generally manufactured,packaged and sold separately, PV installations which include a pluralityof PV generators, e.g., installation 100 a may require unpacking a largenumber of devices, individually coupling each device to itscorresponding photovoltaic generator, and then coupling the powerdevices to one another using cables which may be sold separately aswell. In some embodiments introduced herein, a power device chain isprovided. The power device chain may include a plurality of powerdevices each coupled to at least one other power device using conductorsof appropriate length at the time of manufacturing. Accordingly, powerdevice chains as described herein may be packaged and sold as a singleunit, and deployed as a single unit when installing installation 100 a.For example, power devices 102 a-m may comprise a string of powerdevices or part of a string of power devices, and may be coupled to oneanother during manufacturing. During installation, the string may simplybe strung out alongside photovoltaic modules 101 a-m and each device maybe coupled to its corresponding module quickly and easily, formingphotovoltaic string 316 a.

As shown in FIG. 1A, installation 100 a may include a plurality ofphotovoltaic strings 316 a-n, with a terminal of each photovoltaicstring 316 a-n being coupled to the power bus and the other terminalbeing coupled to the ground bus.

Referring now to FIG. 1B, illustrative system 100 b may share many ofthe same characteristics as illustrative installation 100 a of FIG. 1A,but the wiring of photovoltaic strings may differ in some respects. Forexample, in illustrative system 100 b, each photovoltaic power device103 a-m may be coupled to two photovoltaic generators. For example,photovoltaic power device 103 a may be coupled to generators 101 a and101 b, power device 103 b may be coupled to generators 101 b and 101 c(not shown), and so on. Wiring each photovoltaic string (e.g. 316 a) inthis manner may save money by requiring thinner and fewer cables tocouple the power devices to the generators and to one another.

In the illustrative embodiment show in FIG. 1B, the power devices may beprecoupled to one another during manufacturing, packaged and/or soldtogether, and deployed easily, similar to as described with reference toinstallation 100 a shown in FIG. 1A. For effective system operation andfor easy and fast coupling of the power devices to the photovoltaicgenerator(s) the power devices are meant to be coupled to, theelectrical and/or mechanical design of the power devices used forsystems such as 100 a may differ from the design used for systems suchas 100 b. The pre-coupling, packaging and easy deployment describedherein may be applied to different kinds of power devices used indifferent kinds of photovoltaic systems, regardless of mechanical designand electrical topology details which may be specific to certain powerdevices.

Reference is now made to FIG. 1C, which shows an illustrative embodimentof a photovoltaic string 316 a in which each photovoltaic power deviceis coupled to two photovoltaic modules. In this embodiment, PV powerdevices 108 a-m comprise Buck-Boost DC/DC converters. Additionalcircuitry may be included in power devices 108 a-m, but is notexplicitly depicted in FIG. 1C. Additional circuitry and/or wiringconfigurations may be used to couple power devices to photovoltaicgenerators according to various aspects of the present disclosure.

Referring to FIG. 1D, illustrative embodiments may include photovoltaicinstallation 100 d, comprising a plurality of photovoltaic generators101 a-m each coupled to a power device 122 a-m. Each power device mayhave two outputs, one coupled to a mutual power bus, and one coupled toa mutual ground bus, coupling all the power devices in parallel. In someembodiments, one or more power device 122 a-m may comprise a DC/DCconverter, with each converter's positive output coupled to the powerbus, and the negative terminal coupled to the ground bus. In someembodiments, one or more power device 122 a-m may comprise a DC/ACconverter, with the AC outputs synchronized to allow parallel coupling.In some embodiments including an AC output by the power devices, the ACoutput may be a single phase coupled to the power and ground buses, andin some embodiments three or more phases may be output to more than twobuses. The system may further include the power bus and ground bus beinginput to grid-coupling device 120. In embodiments including a DC outputby the power devices, grid coupling device 120 may include a DC/ACinverter. In embodiments including an AC output by the power devices,grid coupling device 120 may include a transformer. Grid coupling device120 may be similar to or the same as system power device 110 of FIG. 1A,and may comprise safety devices (e.g. sensors, circuit breakers, fuses,etc.) and/or control and/or monitoring devices.

Referring to FIG. 1E, more than one photovoltaic module may be coupledto each photovoltaic power device. System 100 e includes twophotovoltaic modules (e.g. photovoltaic panels or a different type ofphotovoltaic generator) 111 a, 111 b coupled to each other in series,with a photovoltaic power device 112 a coupled in parallel to theserially coupled modules 111 a, 111 b. Similar to other embodimentsdisclosed herein, a plurality of power devices 112 a-x may be coupled inseries to form a photovoltaic string 321 a, with multiple strings 321a-n coupled in parallel between the ground and power buses. In someembodiments, inverter 123 may receive a DC input from the ground andpower buses and output AC power to the grid or home. In similarembodiments, the power devices may be precoupled to one another at thetime of manufacturing, with the conductors coupling the power devicesbeing sized to allow the desired number of photovoltaic generators to becoupled to each power device. For example, if each two PV generators areto be coupled to one another and to a single power device, the length ofeach conductor between power devices being around double the width orlength of each photovoltaic module.

Referring to FIG. 2A, photovoltaic power device 102 may be configured invarious ways. In one illustrative embodiment, photovoltaic power device102 may comprise a casing 231 containing circuitry 230, input terminals210 c and 210 d, and output conductors 220 c and 220 d. In otherembodiments, casing 231 may be replaced by a surface on which circuitry230 is mounted, the surface being snapped to a different part of aphotovoltaic apparatus such as a junction box. In some embodiments,there may be more than two input terminals. For example, someembodiments may include four input terminals for coupling the powerdevice to two photovoltaic modules, the power device processing powerinput from both modules.

In some embodiments, circuitry 230 may include a power conversioncircuit such as a direct current—direct current (DC/DC) converter suchas a buck, boost, buck-boost, Cuk, charge pump, flyback and/or forwardconverter. In some embodiments, circuitry 230 may include a directcurrent—alternating current (DC/AC) converter, also known as an inverteror a microinverter. In some embodiments, circuitry 230 may include aMaximum Power Point Tracking (MPPT) circuit with a controller,configured to extract increased power from the PV generator the powerdevice is coupled to. Circuitry 230 may further comprise a controldevice such as a microprocessor, Digital Signal Processor (DSP) and/oran FPGA. In some embodiments, circuitry 230 may include circuitry and/orsensors configured to measure parameters on or near the photovoltaicgenerator, such as the voltage and/or current output by the generator,the power output by the generator, the irradiance received by thegenerator and/or the temperature on or near the generator. Inputterminals 210 c and 210 d may be coupled to outputs of one or morephotovoltaic modules, and may also be coupled to circuitry 230 forprocessing and/or measuring the power output by the correspondingphotovoltaic module. Output conductors 220 c and 220 d may couple thephotovoltaic power device to adjacent devices, to form a serial orparallel photovoltaic string. The input and output terminals may bephysically connected to different parts of casing 231. The inputterminals 210 c and 210 d may be physically located next to one anotheralong one side of casing 231, with output conductors 220 c and 220 doccupying opposite sides of casing 231, on either side of inputterminals 210 c and 210 d. In other embodiments, the input terminals andoutput conductors may be configured differently, as will be shownherein. The location of the input terminals and output conductors may bechosen considering the layout and wiring design of the system at hand.Mechanical considerations, such as enabling optimal storing of theentire chain of power devices, may also factor into designing thelocation of the input terminals and output conductors. The photovoltaicpower device 102 shown in FIG. 2A may be particularly suited forcoupling to a single photovoltaic generator (in systems such as thoseshown in FIGS. 1A and 5A), since the input terminals are next to eachother, though photovoltaic power device 102 may also be deployed in away that couples it to two generators.

Referring now to FIG. 2B, the input terminals and output conductors maybe configured such that input terminal 210 a is adjacent to outputconductor 220 a, both connected to a side of casing 231, and on theopposite side of casing 231 input terminal 210 b is adjacent to outputconductor 220 b. This illustrative embodiment may be particularly suitedfor coupling photovoltaic power device 103 a to two photovoltaicgenerators (in systems such as those shown in FIGS. 1B and 5B), sincethe two input terminals may be coupled to two generators on either sideof the power device, though photovoltaic power device 103 a may also bedeployed in a way that couples it to a single generator.

Referring now to FIG. 2C, the input terminals and output conductors maybe configured such that input terminals 210 e and 210 f are located onopposing sides of casing 231, while output conductors 220 e and 220 fare located on the other pair of opposite sides of casing. Thus, foursides of the casing contain either an input terminal or an outputconductor. This illustrative embodiment may, in some configurations,enable optimal packaging of the chain of power devices and enable it tobe stored in a compact convenient way. The chain according thisembodiment can be deployed in a way that couples each power device toeither one or two photovoltaic modules.

Referring now to FIG. 3 , the casing 231 may house circuitry 230. Insome embodiments, circuitry 230 may include power converter 240. Powerconverter 240 may include a direct current-direct current (DC/DC)converter such as a buck, boost, buck-boost, flyback and/or forwardconverter. In some embodiments, power converter 240 may include a directcurrent—alternating current (DC/AC) converter, also known as an inverteror a microinverter. In some embodiments, circuitry 230 may includeMaximum Power Point Tracking (MPPT) circuit 295, configured to extractincreased power from the PV generator the power device is coupled to. Insome embodiments, power converter 240 may include MPPT functionality,and MPPT circuit 295 may not be included. Circuitry 230 may furthercomprise control device 270 such as a microprocessor, Digital SignalProcessor (DSP) and/or an FPGA. Control device 270 may control and/orcommunicate with other elements of circuitry 230 over common bus 290. Insome embodiments, circuitry 230 may include circuitry and/or sensors 280configured to measure parameters on or near the photovoltaic generator,such as the voltage and/or current output by the generator, the poweroutput by the generator, the irradiance received by the generator and/orthe temperature on or near the generator. In some embodiments, circuitry230 may include communication device 250, configured to transmit and/orreceive data and/or commands from other devices. Communication device250 may communicate using Power Line Communication (PLC) technology, orwireless technologies such as ZigBee, Wi-Fi, cellular communication orother wireless methods. In some embodiments, PLC signals may betransmitted and/or received over output conductors 220 a and/or 220 b.In some embodiments, a communications link (e.g. an optical fiber) maybe integrated with output conductors 220 a and/or 220 b and may becommunicatively coupled to communication device 250. In someembodiments, a thermal sensor device (e.g. a thermocouple device or aLinear Heat Detector) may be integrated with output conductors 220 a and220 b and may provide temperature measurements (e.g. measurementsobtained at various locations along output conductors 220 a and 220 b)to control device 270. Input terminals 210 a and 210 b may be coupled tooutputs of one or more photovoltaic modules, and may also be coupled tocircuitry 230 for processing and/or measuring the power output by thecorresponding photovoltaic module. In some embodiments, circuitry 230may include safety devices 260 (e.g. fuses, circuit breakers andResidual Current Detectors). The various components of circuitry 230 maycommunicate and/or share data over common bus 290.

FIG. 4A depicts an illustrative embodiment of chain 410. Chain 410 maycomprise plurality of photovoltaic power devices 411 a-c coupled byplurality of conductors 412 a-d. In some embodiments, a chain ofphotovoltaic power devices similar to chain 410 may comprise ten, twentyor even a hundred photovoltaic power devices. In some embodiments, chain410 may be manufactured and/or sold as a single unit. Photovoltaic powerdevices 411 a-c may be similar to or the same as photovoltaic powerdevices described herein, for example, photovoltaic power device 102 ofFIG. 2A, or photovoltaic power device 103 a of FIG. 2B. Conductors 412a-d may be directly coupled (e.g. connected) to the output terminals ofa DC/DC converter or DC/AC inverter included in a photovoltaic powerdevice (e.g. 411 a-c). The length of each output conductor 412 a-d maybe appropriate to enable each PV power device to be coupled tophotovoltaic generators in a photovoltaic string. Since different PVgenerators may have different dimensions, and since the PV generatorsmay be oriented differently during deployment, the distance betweenpower devices (i.e., the length of each output conductor) may vary indifferent chains. However, many PV generators (e.g. PV panels) are ofsimilar dimensions, and PV panels are generally oriented in one of twoways (vertically, aka “portrait”, or horizontally, aka “landscape”), soa chain of photovoltaic power devices (e.g. chain 410) featuring astandard distance between power devices may be deployed manyphotovoltaic systems. For example, photovoltaic panels are generallymanufactured in standard sizes, such as around 65 by around 39 inchesfor residential installations or around 77 by around 39 inches forcommercial installations. Therefore, chains of power devices configuredto be deployed with panels of dimensions similar to those cited abovemay include conductors which are around 39, around 65 or around 77inches long. While the input terminals and output conductors 412 a-d ofillustrative power devices 411 a-c denoted in FIG. 4A are locatedsimilarly to what is shown in FIG. 2B, this does not rule outembodiments in which the input terminals and output conductors arelocated similarly to what is shown in FIG. 2A, or various otherconfigurations without departing from the scope of the presentdisclosure.

Conductors 412 a-412 d may be (e.g. during manufacturing or chain 410)internally connected to circuitry (e.g. circuitry 230 of FIG. 3 ) insidephotovoltaic power devices 411 a-411 c at the time of manufacturing. Forexample, conductor 412 b may, at a first end, be soldered or connectedvia a screw to a power converter or monitoring device in photovoltaicpower device 411 a, and at a second end, be soldered or connected via ascrew to a power converter or monitoring device in photovoltaic powerdevice 411 b. Preconnecting conductors between power devices may reducethe number of connectors (e.g. MC4™ connectors) featured in each powerdevice from four (two connectors for connecting to a PV generator at thepower device input and two connectors for connecting between powerdevices at the power device output). As connectors may be costlycomponents, substantial savings may be realized. Additionally,preconnecting power devices during manufacturing may increase systemsafety. For example, if improperly connected, connection points betweenpower devices may be susceptible to overheating, arcing and/or otherunsafe event which may result in fire. Preconnecting conductors betweenpower devices during manufacturing without use of connectors mayincrease system safety by reducing the number of connection points fromfour per power device to two per power device.

Referring now to FIG. 4B, a chain of photovoltaic power devices 104 maycomprise output conductors which double as ground and power buses of aparallel-connected photovoltaic installation, similar to the systemshown in FIG. 1D. Input terminals 106 may be coupled to the outputs of aphotovoltaic system. Output conductor 105 a may be coupled to the powerbus using a T-connector, and output conductor 105 b may be coupled tothe ground bus using a T-connector. The input terminals 106 and outputconductors 105 a, 105 b are denoted explicitly in FIG. 4B only for powerdevice 104 a, to reduce visual noise. One or more power device 104 a-cmay comprise a DC/DC converter or DC/AC inverter configured to output aDC or AC voltage common to all parallel-connected devices. In someembodiments, one or more power device 104 a-c may comprise a MaximumPower Point Tracking (MPPT) circuit with a controller, configured toextract maximum power from the PV generator the power device is coupledto. One or more power device 104 a-c may further comprise a controldevice such as a microprocessor, Digital Signal Processor (DSP) and/oran FPGA. In some embodiments, one or more power device 104 a-c maycomprise circuitry and/or sensors configured to measure parameters on ornear the photovoltaic generator, such as the voltage and/or currentoutput by the generator power output by the generator, the irradiancereceived by the generator and/or the temperature on or near thegenerator. The power device chain 104 in the illustrative embodimentshown in FIG. 4B may include two long conductors, ground bus 116 andpower bus 115, with PV power devices coupled to the two conductors, withthe distance between adjacent power devices enabling them to be coupledto adjacent PV generators in a photovoltaic installation. The powerdevices may be coupled to the conductors at the time of manufacturing,and may be compactly stored along with the conductors, enabling fast andeasy deployment.

Referring now to FIG. 4C, illustrative embodiments of photovoltaic powerdevice 107 may feature an open casing or lid 232 instead of a closedcasing such as casing 231 depicted in FIG. 2A. Lid 232 may includecircuit-mounting surface 233 which may be used to mount circuitry 230.Circuitry 230 may comprise any and/or all of the components describedherein with reference to other figures. For example, circuitry 230 maycomprise a power converter such as a DC/DC or a DC/AC converter. Asanother example, circuitry 230 may comprise a monitoring device inaddition to or instead of a power converter. In some embodiments, powerdevice 107 may be designed to be connectable to a portion of aphotovoltaic panel junction box, enabling circuitry 230 to be coupleddirectly to the electronics located in the panel's junction box. In someembodiments, PV power device 107 may comprise bypass and/or blockingdiodes to prevent and alleviate mismatch effects in the solar arrayscomprising the PV panel. In some embodiments, direct coupling of the lidto a photovoltaic generator junction box may render external inputterminals unnecessary. Output conductors 234 a-b may be located onopposite sides of lid 232, and may be coupled to additional powerdevices (not depicted explicitly in the figure), forming a chain ofserially connected devices. Similar to other illustrative embodiments,the distance (i.e. the length of the coupling conductor) betweenadjacent power devices 107 may be of appropriate length enablingcoupling of adjacent power devices to adjacent photovoltaic modules in aphotovoltaic installation. The power devices may be coupled to theconductors at the time of manufacturing, and may be compactly storedalong with the conductors, enabling fast and easy deployment.

Reference is now made to FIG. 5A, which depicts a portion of a chain ofpower devices coupled to photovoltaic generators, according toillustrative embodiments. PV generator 101 e may include junction box601 e, featuring two outputs which may be coupled to input terminals 210q and 210 r of power device 102 e. Power generated by the PV generatormay be transferred via the junction box to the power device via theinput terminals 210 q and 210 r, which may be coupled directly to thejunction box. Power device 102 e may further include circuitry 230 (notexplicitly depicted in the figure) which may comprise various elementsas described herein. Output conductor 220 e may couple power device 102e to an adjacent power device on one side (not shown explicitly), whileoutput conductor 220 f may couple power device 102 e to an adjacentpower device 102 f on the other side, with output conductor 220 fcoupling power device 102 f to power device 102 g. To reduce visualnoise, the input terminals and output conductors of power devices 102 f,102 g are not labeled explicitly in the figure. Conductors 220 e, 220 fand 220 g may be of appropriate length to enable fast and easy couplingof each of the power devices to their respective generators, withoutoveruse of conductive cables. For example, if PV modules 101 e, 101 fand 101 g are of standard width of 39 inches and are placed next to oneanother while oriented vertically, each output conductor may be about40-45 inches long.

Reference is now made to FIG. 5B, which depicts a portion of a chain ofpower devices coupled to photovoltaic generators, according toillustrative embodiments. PV generator 101 a may include junction box601 a, to which generator cables 501 a and 501 b are coupled. Powergenerated by the PV generator is transferred via the junction box to thegenerator cables, with cable 501 a coupled to input terminal 210 b ofpower device 102 a, and cable 501 b coupled to input terminal 210 c ofpower device 102 b. Power devices 102 a and 102 b may be coupled to oneanother by output conductor 220 b. Power device 102 a may includecircuitry 230 (not explicitly depicted in the figure) which may comprisevarious elements as described herein. Output conductor 220 a may couplepower device 102 a to an adjacent power device on one side (not shownexplicitly), with input terminal 210 a being coupled to an adjacentpower cable (also not shown explicitly). To reduce visual noise, theinput terminals and output conductors of power devices 102 b, 102 c arenot labeled explicitly in the figure. Conductors 220 a, 220 b and 220 cmay be of appropriate length to enable fast and easy coupling of each ofthe power devices to two adjacent photovoltaic modules, without overuseof conductive cables. For example, if PV generators 101 a 101 b and 101c are of standard width of 39 inches and are placed next to one anotherwhile oriented vertically, each output conductor may be about 40-45inches long.

Referring to FIG. 5C, illustrative embodiments may include a pluralityof PV power devices 104 a-c, each featuring two input terminals 106(only labeled explicitly for power device 104 a) coupled to aphotovoltaic generator's junction box (e.g., 601 a). The photovoltaicpower may flow via the junction box and input terminals to the PV powerdevice. The power device may include output conductor 105 a, which iscoupled via a T-connector to a ground bus, and output conductor 105 b,which is coupled via a T-connector to a power bus. The ground bus andpower bus may be coupled to the output conductors of each power devicein the chain, thus coupling all the photovoltaic modules in the stringin parallel. The distance between adjacent PV power devices may enablethem to be coupled to adjacent PV generators in a photovoltaicinstallation. The power devices may be coupled to the two conductors(the ground and power buses) at the time of manufacturing, and may becompactly stored along with the conductors, enabling fast and easydeployment.

Referring now to FIG. 6 , some illustrative embodiments include astorage device used to store a chain of power devices in a way thatenables convenient storing and fast and easy deployment of the chain ofpower devices. A chain of photovoltaic power devices may comprise PVpower devices 102 coupled to one another by output conductors 220. Thechain may be stored by being wound around storage device 400. In theillustrative embodiment depicted in FIG. 6 , storage device 400 is acylindrical reel, though other shapes may be using for winding. Acylindrical shape may make deployment easier, as a cylindrical reel maybe rolled along the ground in a photovoltaic installation, much likecabling reels. The storage device may be designed to allow the chain ofpower devices to be packaged efficiently. For example, if the storagedevice is similar to the cylindrical reel depicted in FIG. 4 , thediameter of the reel may be chosen considering the length of theconductors coupling the power devices, so that when the chain is woundaround the reel, the power devices may be located next to one another onthe reel, pressed tightly together for compact storing.

In some embodiments, an apparatus includes a plurality of power devicesand a plurality of photovoltaic generators connected to the powerdevices. The power devices may include an input terminal, a commonterminal and first and second output terminals. An input terminal of afirst power device may be connected to a first power source terminal ofone of the plurality of photovoltaic generators, a first output terminalof a second power device may be connected to a second power sourceterminal of one of the plurality of photovoltaic generators, and asecond output terminal of the second power device may be connected to acommon terminal of the first power device. The first and second outputterminals may output a common output voltage, with a total outputcurrent flowing through the power device (e.g. a photovoltaic stringcurrent where the power device is part of a photovoltaic string) beingdivided between a first output current flowing through the first outputterminal and a second output current flowing through the second outputterminal. The first output current may further flow through a connectedphotovoltaic generator, and in some embodiments, the power device may beoperated to provide a first output current corresponding to a MaximumPower Point current of the photovoltaic generator. The power device maybe operated to provide a second output current corresponding to adifferential current between the total output current and the firstoutput current.

In some embodiments, the first output terminal may comprise a connectordesigned to be connected to a photovoltaic generator terminal, forexample, using an MC4™ connector. In some embodiment, the second outputterminal and the common terminal may comprise conductors preconnected tothe power device and other power devices (e.g. conductors 220 c and 220d of FIG. 2A, or conductors 220 a and 220 b of FIG. 2B). Dividing thecurrent of a power device into two or more portions may create smallercurrent portions that allow for cables which may be thinner and cheaperthan those which would otherwise be needed.

At least one of the power devices may include a combiner box configuredto couple to a plurality of photovoltaic strings and to combine powerfrom the plurality of photovoltaic strings. One or more power devicesmay include one or more sensors or sensor interfaces configured tomeasure or to receive measurements of one or more parameters associatedwith the plurality of photovoltaic generators. One or more power devicesmay include one or more safety switches configured to disconnect and/orshort circuit the photovoltaic generators upon detection of a predefinedpotentially unsafe condition or in response to a manual trigger. Themanual trigger may include activation of a rapid-shutdown switch orbutton.

In some embodiments, the power device may include output conductorsconfigured to transmit and/or receive PLC signals. A communications link(e.g. may be integrated with output conductors and may becommunicatively coupled to a communication device. A thermal sensordevice may be integrated with output conductors and may providetemperature measurements to a control device associated with theapparatus. The thermal sensor device may include a thermocouple deviceand/or a linear heat detector. Temperature measurements by the thermalsensor device may be obtained at one or more locations along the outputconductors.

In some embodiments, an apparatus includes a plurality of power devicesand a plurality of conductors connecting, each connecting one powerdevice to at least one other power device. A first conductor may beconnected between an input of a first power device and a first output ofa first power generator. A second conductor may be connected between anoutput of the first power device and a second output of first powergenerator. A third conductor may be connected between an output of asecond power device and the common terminal of the first power device.The conductors may be internally connected to circuitry inside arespective power device. At least one of the plurality of conductorsmay, at a first end, be soldered or connected via a screw to the powerdevice. A second end of the conductor may be soldered or connected via ascrew to another power device. Specifically, the first end and secondend may each be connected to a power converter or monitoring device in arespective power device.

Other embodiments may consider alternative storage techniques, such aspacking power device chains into boxes, winding the chain aroundmultiple poles, and the like.

Although selected embodiments of the present invention have been shownand described, it is to be understood the present invention is notlimited to the described embodiments. Instead, it is to be appreciatedthat changes may be made to these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined bythe claims and the equivalents thereof. Further, elements of oneembodiment may be combined with elements from other embodiments inappropriate combinations or subcombinations. For example, conductors 234a-b of FIG. 4C may be located at a same side of lid 232, similarly to asshown with regard to terminals 210 c and 210 d of FIG. 2A. As anotherexample, a chain of power devices may connect a plurality ofphotovoltaic generators in parallel, as shown in FIG. 5C, wherein eachof the plurality of photovoltaic generators comprises a plurality ofserially connected photovoltaic panels (as shown in FIG. 1E) orphotovoltaic cells.

In illustrative embodiments disclosed herein, photovoltaic generatorsare used as examples of power sources which may make use of the novelfeatures disclosed. Each PV generator may comprise one or more solarcells, one or more solar cell strings, one or more solar panels, one ormore solar shingles, or combinations thereof. In some embodiments, thepower sources may include batteries, flywheels, wind or hydroelectricturbines, fuel cells or other energy sources in addition to or insteadof photovoltaic panels. Systems, apparatuses and methods disclosedherein which use PV generators may be equally applicable to alternativesystems using additional power sources, and these alternative systemsare included in embodiments disclosed herein.

The invention claimed is:
 1. An apparatus comprising: a serial stringpackaged for deployment in a photovoltaic power generation system, theserial string comprising: a plurality of conductors; and a plurality ofpower devices, each comprising first and second input connectors andfirst and second output connectors; wherein each conductor of theplurality of conductors is connected between the first output connectorof one of the plurality of power devices and the second output connectorof another of the plurality of power devices to connect the plurality ofpower devices in series, and wherein each power device of the pluralityof power devices is configured to be connected at its first and secondinput connectors to a respective predetermined number of powergenerators of a plurality of power generators, the respectivepredetermined number being associated with lengths of conductors, of theplurality of conductors, connected to the power device at its first andsecond output connectors.
 2. The apparatus of claim 1, wherein eachpower device of the plurality of power devices further comprises atleast one of a direct current to direct current (DC/DC) converter or adirect current to alternating current (DC/AC) converter.
 3. Theapparatus of claim 1, wherein one or more power devices of the pluralityof power devices are configured to regulate an output of one or morepower generators connected to the one or more power devices.
 4. Theapparatus of claim 1, wherein each power device of the plurality ofpower devices further comprises a communication device.
 5. The apparatusof claim 1, wherein each power device of the plurality of power devicesfurther comprises at least one of a residual current device, a fuse, ameasuring device, or a monitoring device.
 6. The apparatus of claim 1,further comprising an instrument configured to store the plurality ofpower devices and the plurality of conductors by winding the pluralityof power devices and the plurality of conductors around the instrument.7. The apparatus of claim 6, wherein the instrument is at least one of aspool, a bar, or a frame.
 8. A method comprising: connecting a pluralityof power devices using a plurality of conductors, wherein each conductorof the plurality of conductors is disposed between two adjacent powerdevices of the plurality of power devices, wherein a first conductor ofthe plurality of conductors is connected between a first power deviceand a second power device of the plurality of power devices, and whereinthe first power device is configured to be connected to at least onefirst power generator, and the second power device is configured to beconnected to at least one second power generator; configuring a lengthof the first conductor of the plurality of conductors based on a numberof the at least one first power generator to which the first powergenerator is configured to be connected and further based on a number ofthe at least one second power generator; and packaging, for deployment,the plurality of power devices and the plurality of conductors as asingle unit.
 9. The method of claim 8, wherein the connecting theplurality of power devices is performed during a manufacturing phase,and wherein the method further comprises storing the plurality of powerdevices and the plurality of conductors as the single unit.
 10. Themethod of claim 8, wherein the packaging the plurality of power devicesand the plurality of conductors comprises winding the plurality of powerdevices and the plurality of conductors around at least one of a spool,a bar, or a frame.
 11. The method of claim 8, wherein the first powerdevice is configured to regulate an output of the at least one firstpower generator.
 12. The method of claim 8, wherein one or more powerdevices of the plurality of power devices further comprise acommunication device.
 13. The method of claim 8, wherein each powerdevice of the plurality of power devices comprises at least one of aresidual current device, a fuse, a measuring device, or a monitoringdevice.
 14. A system comprising: a plurality of photovoltaic (PV)generators; a plurality of power devices connected by a plurality ofconductors and packaged for deployment, wherein each conductor of theplurality of conductors is disposed between two adjacent power devicesof the plurality of power devices, wherein each power device of theplurality of power devices comprises an input connected to at least onePV generator of the plurality of PV generators, and wherein a length ofeach conductor of the plurality of conductors is determined based on anumber of one or more PV generators, of the plurality of PV generators,connected to the two adjacent power devices; and at least one directcurrent to alternating current (DC/AC) converter connected to at leastone power device of the plurality of power devices.
 15. The system ofclaim 14, wherein the at least one PV generator is configured togenerate DC power received respectively by each power device, andwherein the at least one DC/AC converter is configured to receive inputDC power from the plurality of power devices via the at least one powerdevice and output AC power based on the input DC power.
 16. The systemof claim 14, wherein the plurality of power devices and the plurality ofconductors are packaged by winding the plurality of power devices andthe plurality of conductors around at least one of a spool, a bar, or aframe.
 17. The system of claim 14, wherein each power device of theplurality of power devices is configured to increase an output of the atleast one PV generator connected thereto.
 18. The system of claim 14,wherein each power device of the plurality of power devices furthercomprises a communication device.
 19. The system of claim 14, whereineach power device of the plurality of power devices further comprises atleast one of a residual current device, a fuse, a measuring device, or amonitoring device.
 20. The system of claim 14, wherein each power deviceof the plurality of power devices is configured to regulate an outputthe at least one PV generator connected thereto.